1. Field of the Invention
The present invention relates to a substrate used to measure electrical characteristics of an electronic component while mounting the electronic component thereon and being connected to a measurement device during measurement.
2. Description of the Related Art
Electrical characteristics of electronic components, such as filters and duplexers, may often be measured to determine whether they are within specifications. Electrical characteristics of an electronic component can be measured by mounting the electronic component on a substrate used to measure electrical characteristics and connecting the substrate to a measurement device. One typical example of such a substrate is a configuration in which a component mounting electrode arranged to be connected to an output terminal of an electronic component thereon and a connector arranged to be connected to a measurement device are connected by a coplanar line having specific impedance. Electronic components have various sizes and different terminal locations, and it is necessary to prepare a substrate used to measure electrical characteristics so as to support each of various types of electronic components.
FIG. 1A is a plan view of a first configuration of a substrate used to measure electrical characteristics. A substrate 101 includes coplanar lines 104A to 104C, a front-surface ground electrode 105, a back-surface ground electrode (not illustrated), and via electrodes 107. The coplanar line 104A includes a first end that is arranged to be connected to an electronic component and that is arranged in a substantially central portion of the front surface of the substrate and a second end that is arranged to be connected to a connector arranged to be connected to a measurement device and that extends to a right side of the substrate illustrated in the drawing. The coplanar line 104B includes a first end arranged in the substantially central portion of the front surface of the substrate and a second end extending to a left side of the substrate. The coplanar line 104C includes a first end arranged in the substantially central portion of the front surface of the substrate and a second end extending to the left side of the substrate. The first ends of the coplanar lines 104A to 104C function as a component mounting electrode 102 to be connected to an output terminal of an electronic component. The front-surface ground electrode 105 extends over substantially the entire front surface of the substrate and is separated from the coplanar lines 104A to 104C. The back-surface ground electrode (not illustrated) extends over substantially the entire back surface of the substrate. The via electrodes 107 extend along the coplanar lines 104A to 104C and provide continuity between the front-surface ground electrode 105 and the back-surface ground electrode (not illustrated). The substrate 101 is used for a 3-port electronic component including terminals that are arranged substantially symmetric about a line.
FIG. 1B is a plan view of a second configuration of the substrate used to measure electrical characteristics. A substrate 201 includes coplanar lines 204A to 204D, a front-surface ground electrode 205, a back-surface ground electrode (not illustrated), and via electrodes 207. The coplanar line 204A includes a first end arranged in a substantially central portion of the front surface of the substrate and a second end extending to a right side of the substrate. The coplanar line 204B includes a first end arranged in the substantially central portion of the front surface of the substrate and a second end extending to a left side of the substrate. The coplanar line 204C includes a first end arranged in the substantially central portion of the front surface of the substrate and a second end extending to the left side of the substrate. The coplanar line 204D includes a first end arranged in the substantially central portion of the front surface of the substrate and a second end extending to the right side of the substrate. The first ends of the microstrip lines 204A to 204D function as a component mounting electrode 202 to be connected to an output terminal of an electronic component. The substrate 201 is used for a 4-port electronic component including terminals that are asymmetric about a line.
For electronic components, such as filters and duplexers, a plurality of types of substrates having terminals arranged as mirror images may be required. The substrate 101 in FIG. 1A is used for a plurality of types of electronic components including terminals that are substantially symmetric about a line. In contrast, because the substrate 201 illustrated in FIG. 1B is used for an electronic component including terminals that are asymmetric about a line, the substrate 201 illustrated in FIG. 1B cannot be used to measure electrical characteristics of another electronic component having terminals arranged as mirror images of those in that electronic component. Therefore, to measure electrical characteristics of each of two such electronic components, it is necessary to provide a different substrate for each of them. This results in an increased cost of production of substrates used to measure electrical characteristics and an increased number of items of inventory control.